ESMO 2026: CSPC and Alphamab’s HER2 Bispecific ADC JSKN003 Achieves 100% ORR in Phase II First-Line Gastric Cancer Study A Phase II trial of JSKN003, a HER2 bispecific antibody-drug conjugate developed by CSPC Pharmaceutical Group and Alphamab Oncology, reported a 100% confirmed objective response rate (ORR, 14/14 patients) in treatment-naive patients with HER2-positive advanced gastric or gastroesophageal junction adenocarcinoma in Cohort B. Presented at ESMO 2026, the trial evaluated three regimens: JSKN003 plus sintilimab and capecitabine (Cohort A, ORR 71.4%); JSKN003 plus sintilimab, capecitabine, and anitumab (Cohort B, 100%); and JSKN003 plus SG001, capecitabine, and oxaliplatin (Cohort C, 50.0%). Grade ≥3 treatment-related adverse events occurred in 57.1%, 28.6%, and 100% of Cohorts A, B, and C, respectively. No treatment-related deaths occurred. Survival and response durability data remain immature.